The present invention relates to Flight Management Systems, and more particularly, to a method of determining the performance characteristics of an aircraft/engine based on actual data gathered and saved from each flight.
Present day systems utilize the "rule of thumb" technique in predicting the performance characteristics of the aircraft/engine (s), whereby the pilot, based on previous experience, makes a reasonable estimate of the performance characteristics. Some present day aircraft/engine performance characteristic systems have also been devised which include a custom performance computer for preselected aircraft/engine combinations. These systems utilize "average parameters" for a predetermined model/class of aircraft/engine combination. It is well understood that even within the same model, parameters/characteristics will vary between individual aircraft/engine(s). Clearly, the "average parameters" of the model do not have incorporated therein any features or characteristics unique to an individual aircraft/engine combination.
The disadvantages of these present day systems is that they have inaccuracies associated therewith. The "rule of thumb" method can be very inaccurate since it is difficult to compensate for temperature of the air, weight of the aircraft,.... Also, this method usually adds to the pilot workload at a time when the pilot is already very busy. The custom performance computer does not account for manufacturing tolerances and the wear/degradation of parameters resulting from aging and usage. Further, this system does not adjust to different pilot techniques.
The present invention overcomes the disadvantages of the present day systems. The method of the present invention makes performance predictions for an individual aircraft and engine(s) using parameters which are "learned" from flight to flight. The data, which is used by the method of the present invention for predicting performance characteristics, is initialized with reasonable values of specific performance parameters. The method of the present invention includes the adjustment (updating) of specific performance parameters resulting from each flight. Thus, the performance characteristics of a given aircraft/engine combination are learned from flight to flight for use in future flights of the given aircraft/engine(s). The learned parameter technique of the present invention thereby adjusts to changes in the aircraft/engine due to aging, is tailored to a specific airframe/engine(s) combination, and accounts for manufacturing tolerances.